import { Console, Data, Effect, Layer, Metric } from "effect"

class RuntimeMetricsError extends Data.TaggedError("RuntimeMetricsError")<{
  readonly operation: string
}> {}

const program = Effect.gen(function*() {
  // Create a concurrent workload to demonstrate fiber metrics
  const heavyWorkload = Effect.gen(function*() {
    // Simulate concurrent operations
    const tasks = Array.from({ length: 10 }, (_, i) =>
      Effect.gen(function*() {
        yield* Effect.sleep(`${100 + i * 50} millis`)
        if (i % 4 === 0) {
          // Simulate some failures
          return yield* new RuntimeMetricsError({ operation: `task-${i}` })
        }
        return `Task ${i} completed`
      }).pipe(
        Effect.catchTag("RuntimeMetricsError", () =>
          Effect.succeed(`Task ${i} failed`))
      ))

    // Run tasks concurrently
    const results = yield* Effect.all(tasks, { concurrency: 5 })
    return results
  })

  // Enable runtime metrics collection for our workload
  const workloadWithMetrics = Metric.enableRuntimeMetrics(heavyWorkload)

  // Execute the workload
  const results = yield* workloadWithMetrics

  // After execution, we can inspect the runtime metrics
  // The following metrics are automatically collected:
  // - child_fibers_active: Current number of active child fibers (Gauge)
  // - child_fibers_started: Total child fibers started (Counter, incremental)
  // - child_fiber_successes: Total successful child fibers (Counter, incremental)
  // - child_fiber_failures: Total failed child fibers (Counter, incremental)

  yield* Console.log(`Workload completed with ${results.length} results`)

  // Get all metrics including the runtime metrics
  const allMetrics = yield* Metric.snapshot
  const runtimeMetrics = allMetrics.filter((m) =>
    m.id.startsWith("child_fiber") || m.id.includes("fiber")
  )

  yield* Console.log("Runtime Metrics:")
  for (const metric of runtimeMetrics) {
    yield* Console.log(`  ${metric.id}: ${JSON.stringify(metric.state)}`)
  }

  return results
})

// Alternative: Use the layer version for broader application coverage
const BaseAppLayer = Layer.empty // Your base application layers
const AppLayerWithMetrics = BaseAppLayer.pipe(
  Layer.provide(Metric.enableRuntimeMetricsLayer)
)
const programWithLayer = program.pipe(
  Effect.provide(AppLayerWithMetrics)
)